Magnet-rail for electric pianos.



M. L. SEVERY a; G. B. 's-INGLMLR. MAGNET RAIL POR ELEG'TRG PIAN, APPLIGATIO'N FILED AUG/7, 1905.

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M. L. sig/VERY L G. B. SINGLAIR.

MAGNET RAIL POB. ELECTRIC PIANOS.

APPLICATION FILED AUG.7,19V05. 1,097,052. Patented may 19, 1914.

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MELVIN L. SEVERE?, OF ARLINGTGN HEIGHTS, AND GEORGE B. SINGLAIR, OF

W'INTHBO, MSACHUSETTS. ASSIGNORS T0 CHORALCELO .MANUFACTUR- NG COMPANY. A. CORPORATION GF MAINE.

MAGNET-BAIL FR ELECTRIC PIANOS.

Specification of Letters Patent.

Patent-ea May-j o, 1 oi i.

Application filed August 7', 11905. Serial No. 273.201. y'

To all whomy t may cof/,conm

Be it known that We, MELVIN 'L SEVERY, of .firling'ton Heights, in the county of Middlesex, State of Erlassachusetts, and GEORGE y lllinthrop, in the county 'of Sulfolly said State, both citizens of the United Staten-have invented certain new and useful improvements in Magnet-Rails for Electric PianoS, of whichV the following a full, clear, and exact description.

This invention :is in the field of pianos wherein the strings are Vibrated by means of magnetic pulsations communicated thereto, and the object of this inyention is the construction of improved means for supporting and moving such magnets by `which the magnetic pulsations are conveyed to the strings.

4in certain copending applications We have eher: 7 deecribcd and claimed, in Sonie instance broadly and in others more specilicelly, features which :ire illustrated and def scribed. in the pre1-ent aj'iplication, but which are not herein clam; d or are here claimed only in the :specih cinc-struction or combination expressed. In olhf copending applications we have broadly claimed the art oi" producilif; musical, tones, which art is involved but is not claimed in the present application. All ina tters Set forth and claimed in copending applications filed in our joint names, or in the naine of either of us, and not definitely expressed in the claims hereof, are expressly saved and reserved for one or another of Said copendingj apjilications, in which such niatter are claimed or intended lo he (donned. Amongr these concluding applirutione may be noted the llollowiner joint applications: Serial No. 273.199, liled iiugrust 7. 'llOLj Serial No. j 1510.1; Serial lilo. 302.331, filed llebruary 2li, 11106; Serial No. 377,571, filed .lune o, i907; `Serial N t.375),711l, tiled June 15), 1907; Serial No. 280,997, filed .lune 26, 1907; Serial No. 537,257. liled January 10, 1.910; Serial No.

7llLf'3. filed Julyl 20, 1912; Serial No. '753,013. `lilcd lrlarch 8. 1913; Serial `No. 7l' filed January 3l, 1913; and Serial snee, i. 757,872. tiled March 2li, 1913. llc'lfcrrixrg lo the drawirigsfforiuiug ,parla of this specilicalzion, liig'uro 1 is an elevation i 1 le piano With which the Same is comme'.- f l showing portions oi the sides ot thc 1J-case in ficctiun. Fig. 2 a View parlly .273202.-liled August 7,.

ic iuaguetu'ail looking' i'roni in front j in elevation and partly in section, of the 'means lor adjusting the pivot-al supports of the magnet-rail, showing also the device by which the magnet rail is movedtoward and fromithe piano-strings for the-purpose of lvcreating diminuendo and crescendo effects,

Il and otherwise Varying the loudness of the j music, said View being' rtaken on the zline l 2-2 looking to the left or inthe direction of the arroiveand showing the parts-more widely separated than in Fig. 3,\for greater clear-ness of illustration. Fig. 3 is plan jyiew of the magnet-rail, showing theV piano j case sides 1n section. Fig. 3n is a perspective View of one of the magnet rail supports.

| Fig. 'ul-eis a sectional elevation ol" themagnetrail on larger Scaleshowing adjusting dcvice.

The pian-o strings 10, as indicated by the dots in Fig.l 3, rise iu a vertical plane iin- -mediately in front'of'the magnets 20, and though usually placed in groups of two or three to a note, and hence two or 'three to a magnet, but one string is indicated to a magnet. i

The magnet-rail consists ofthe boards 21, 22 preferably of wood, but of any suitable non-condncting material., and thev cast-iron supporte 23, 2l carrying said boards. Said supports or bars are each formed with two arms 25 pivotcd to adjustable supports 26 clamped by screws 29 `to the sidcs'of the slots fin Said supports. By turning the set screws 28 held in the xed castings 27, said supports can be accurately adjusted to Ibringr the magnets 20 to the exactl quired to properly actuate the-strings.- The not needed.l The means for thus movingsaidthe rock-shaft'f arm SI' link 3G 'oininof 7 3 i D arm 33, canne-edge 39.,

` frifl urni' and ruil;

rod 531 and pedal lever 30, in addil; i tcnfrir'm spring' 85H for pressmg the v j parts composing the magnet-rail conslsts or l piano-case; said screws passing vthronfglr positions re .amplitude of opposition to the action of said cam-wedge. By depressing the cntl of the pedal lever 30, said cam-Wedge is raised, and,y by its action on the arm 33, the magnets 2O are moved away from the strings. "lhe descent of said wedge allows the magnets to return to their normal positions with respect to the strings,

preferably, in this case, that ot strongest inliucnce and loudest tone. To more clearly illustrate the parts in Fig. thc-arms Q5 are shown abnormally elongated; hut. their cor- As shown in Fig. '3, the surface of the cam-wedge 32 where it contacts with the end l l l i l i drawn by themovement of the rail through an equal distance, the differences in e-tleety upon the strings resonance would be much more marked per unit el? distance in the eases of the high notes than the lower ones, where the magnets are normallyT set at a farther distance from the strings 'because of their greater amplitude of vibration. This law, whereby a rail hinged at 26 and haring its upper magnet at a proper distance from said hinge causes the magnets to undergo a of the arm 33, is not straight. but is so eong caved that, the beginning ot' its action upon the strings. it Cannot be applied, but an ensaid. arm is niueh less relative to the move-- ment of said wedge and pedal 30. than at the latter part ot' said pedal`s movement'.

lYe design this ditl'erenre to be sntlirient to cause equal arcs of mtnfenient on the part ot t said pedal to produce uneipial movtnnentsl of 3 l. tionetl at a considerable distance therefrom` the magnet rail and henee of the eleetromagnets 20. of Fig. Q. that when the sharper partV ot the lt evident. from inspection i cam-wedge is acting on the arm 735i the eleetrolnagrmt'.`l 2t) are farthest from then' strings.

while the wider parts ol' the wedge are arting on said arm when the elet-trlnnaefnetsl are nearer their strings. lnasmueh as the electrtnnagrnetsI when close to the strings art far more powerl'ullv than when at a eonsiderable distant'e therefrom. it is manifest that, by adding a slight increase to the dis'- tanee between a magnet and its string, a .deerease 1na be caused in the magrnetk` pull 'thereon equal to adding` double sut-h increase to the distance ot a magnet l'rom itsl `strilng'wlien the latter members are larther removed from each other. l `or example. it' a. magnet be one sixty-fourth ot an int-h away from its sonorous body` another sixt fourth pots it twit-t` as l'ar awav. whereasI a SiXty-fourth of an inth added to the distance of a magnet` alreatlv an eighth otl an inch removed, would be vlar less noticeable in effect. Hence `the ein-re ot the part 32 is shaped as illustrated in Fin'. 2 l'or tln` purpose of enabling'equal movementsl ot the pedal t0 produce sensiblv equal changes in the loudness ol' the musical tones. llv thus arranging the magneta'ail. the magnets` in the vicinity of the. joint ltare moved through a proportionably greater distance from the, strings than are the. ones near either extremity. This mighthe thought fat-al to thel operativeness ot the device` but is, on the contrary. a vitally iinportant feature. 'lhe reasons are that, the vibration of the highest. strings is comparatively limited. and considerable energy is lrequired to vibrate them; consequently the magnets an and should be set normally very close to them. if, now, all the magnetsv were withsensibly uniform increment or decrement in their etfect upon the strings by the normal angular movement of the treble end oit the rail. holds good for substantiall;Y two-thirds ot the notes` but tor the lower one-third et' tirelv reverse arrangement. must be made. ln the ease of decp-bassy strings, their amplitude of, vibration is so veriv grei'tt that. to keep them from striking their magnets when vibrating. the latter must be normally` posi- (lonsequentlv. it' their magnets were withdrawn in the same proportion to which the); would be in ease the magnetaail were one intlexible whole and pivotetl at its righthand or treble end. then said magnets wtaild be obliged to remove bevond the abilita' trl effectively inlluentingg their stringi ln order that unil'orm variations ol' the pedal ma \v produce lsimilar uniform 'variations in the londness of the various notes'.

we havedetermined that it is i'ieressarv that each magnet shoul. have its proper nei-mal distance trom its strings and its proper 1n dividual variation therefrom as the resnlt of the movement of the pedal. This varia tion in distance is individual to eaeh magrnet. but is proportionate to tht` angular dis` placement of a rail hun;r at its two ends with a properly located and operative joint intermediate thereof: and magnets eorreetl \v positioned with respect to their distance from said two ends.

lWe have found, after mueh experiment and whether supported hiv theor)v or not. that` the magnet-rail provided with terminal pivots or hinges and properl)v loratel intermediate maximum .vitlulrawal is' a convenient way lto produce the best results as to uniform and proper variationsl in tone loud ness'. As shown in Fig. 2. the ram-wedge. 32 has its face suitably eoncaveil for the purpose of perfectly varying the degree ot 'the magnetrails departure from the strings relative to the motion of the said wedge and oli its pedal by which the latter is operated. rlhis malgnet-rail is a ver v important part' otx the electric piano set Vforth in our companion 5 to render all the harmonic vibrations nbstantiallv uniform, it is desirable to tone don'n ythe loudness of a few of the various combinations. Eight being the total numlier which We find in practice available for use, tliree of these combinations are all that thusrequire softening. To eilect this s0ftlening, we have devised means wherehir the movement of the harmonic controller as itI reaches said three con'ibinations', automaticallf.r ren'ioves the magnet-rail a proper dis- .tanre from the strings. One form of device for this'purpose is illustrated in Fig. 4. Here it will he seen that the. linl: 36 which is elsewhere shown unbroken, is centrally jointed, as at 40, ind permitted to normally sag at such joint a short distance. This lioint supported hy the rod H carried at its lower end hy a lever t3 pivoted at 45. This lever in turn supported by a frictionfri'illfist riding on the segment cam t6 turning' with the harmonie controller. in this segment are three canrprojeotions 4S located at points to come hcueath the roll 44 lwhen the controller brushes 79 touch the with every variation in varying possible.

frequency of interruption. rlhis factor is of such importance that we have found in practice that it outweighs all other considerations.` it is mani, testify futile to attempt vto get any proper gradations in tones or constancy of musical ett'ect unless-this factor he met With great care. llt Will readily be seen that the insertio'n ot such small merenients of resistance into the line as would norrnall57 occur in small, expression-pedal movements would he of no avail unless these exceedingly large, greatly varying otitious resistances were insome Way con'ipensatedtor. rhis com` pensation has been one that has engaged our liest attention, and required n'icle range of experimentation. Moreover. there are a oonsiderahle number ot other factors which complicate the proposition; as for example, the law of inverse squares, and its coinloination with the law governing the magnetic shell; thearying resistentes to vibration of 'diiering sonorous bodies; their Widely amplitudes of vibration and volumes: the magnetic lag' of the iron; the varyingr time constants; sellinduetion, and other iifonsiderations.

Among' the Ways in which We haveiallowed tor these considerations are the, tolcontacts TO appropriated to the three torte lowing: By varying the windings for the g5 harmonic.combinations. Hence, every time eleotromagnets controllingl the Strings, vthe harmonicconlrolloi'-h1\1slies reach anyv which is more economiealand therefore prefof said't-hree rows of contacts, the cam-proeral'ile to the insertion ot' auxiliary resistjections raise the. lever l2 and rod lll. and anves; such varying windings being set thcrehv hringiA `the jointl() into a rightline he- `torth .in application Serial No. 380.987; and .MQ

hlv i-'aryingr the distances o the magnets troni their respective strings; and by un? equally varying' vtheir icrements of movetiveen the ends ot the link 8G, consequently movinfgrthe nian'uetaziil the desired distance 'farther' troni the strings l0. iilthough we haveillnsti-ated the seg'nient 4G as tixed to nient for exl'iression purposes, as disclosed ,Y

'an'iperesz vet when the current ther arm 73 carrying the baril to which they brushes are attached; said arin boingv pivotally` lsupported at Si' and provided with oounterhalanee spring' 77, vet we do not r@- strict ourselves thereto; inasmuch as said cain'lniav have its independent pivotal support and he operated hv suitable connections4 with the'parts which actuate said harmonic `controller. The lower ond of said rod l-l is preteral'ily threaded and provided with nuts 42 for the purpose of adjusting,` the normaljiosition o the joint 40, and the normal positions ot the magnets with respect to their strings.

1Vllhat is called fictitious resistance iu alternating current circuits we have discovered alsooccurs in kind inrapidly pulsatcd currents of constant polarity. For example, a circuit having' six ohms resistance at Q5 volts would nornmllv talle upward ot :tour broken v. the an'nucter will n onohalt miniere; titty ohms resistA with sulliciont rapidit show materiali)I lesa l heliuvii'ip'. as il upnuir-.i ot' Iin l l l l lanas' cfpial. the resistance will vary :een inserted in the line; and.' other i 'i si n .i i more cioseiy incinte nan aie tue i n this present 4riding' resista nces which can he, inserted into the lines for musical expression. said resislances varyingl with respect. to the considerations above set forth.

What We claim as our invention and for which we desire Letters Ritent is as follows, to Witl. .t inns-ical instrument provided with. a multiplie-it)YV ot sonorous bodies of differenty pitch. electroniagnets for the actuation of said liodies, means for delivering; properlyy tiniedelertric pulsations to. said electromagnets, and supporting means for the latter, adjacent eleotromannets being located at dii/ferent distances from their respective sonorous bodies.

` 2. A musical instrument. provided with a u'iultipliri'fv of sonorous hodies of dilerent. pitch. electromagnets presenting their polos to sa id bodies. n'ieans for delivering;l properly timed eleetrit pulsations to said electro1nagnots, and supporting` ineans tonthe latter. the electroniagnets associated with the sonovous hodies of higheet pitoh lie-ingr l application; and also by prof..d

bear the relation of armatures, and means for delivering properly timed electric pulsations to said electromagnets, the latter being located at differing distances from their so norous bodiesA 4. A musical instrument comprising mag netically attractive sonorous bodies, electromagnets to which said bodies bear respectively the relation of armatures, and means for delivering to said electromagnets properly timed electric pulsations, the electromagnets actuating the upper treble sonorous bodies being located nearer to their associated bodies than are the electromagnets lower down the scale to their associated sonorous bodies.

A musical instrument comprising magnetica'lly attractive sonorous bodies, electromagnetsto which said bodies bear respectively the relation of armatureinand means for delivering properly timed electric pulsations to said electromagnets, the electromagnets actuating the low bass sonorous bodies being' located nearer to said bodies than are the intermediate sonorous bodies to their associated electromagnets.

6. A musical instrument comprising tuned sonorous bodies, electromagnets for their actuation, and means for deliverin properly timed electric pulsations to said e ectromagnets, the intermediate electromagnets of the instrument being located farther from their sonorous bodies than are the electromagnets at the extremities of the instrument from their associated bodies.

7 A musical instrument comprising magnetically attractive -sonorous bodies, electromagnets to which 4said bodies bear the relation of armatures, and means for delivering electric pulsations to said electromagnets, the electromagnets of the upper treble sono-I rous `bodies being very close to the latter, the 10W bass sonorous bodies being sensibly .farther from their electromagnets than the treble bodies, and the intermediate sonorous bodies being farther still 'from their electromagnets.

8. A musical instrument having magnetically attractive sonorous bodies, electromagnet's to which said bodies respectively bear the relation of armatures, and means including circuits for delivering to said electromagnets properly timed electric impulses, said electromagnets being placed at dilerent distances from their respective sonorous bodies, such distances being regulated in accordance with the various amplitudes of vibration of the sonorous bodies and the various values of the impedance interposed. in the aforesaidcircuits as the result of the operating periodieities..

able controlling member or simultaneously l moving said supporting means and electro-A magnets relative to the associated sonorous bodies, equal movements of said controllingr member moving adjacent electromagnets through unequal distances, whereby equal movements of said controlling member produce sensibly equal changesin the loudness ofthe musical tones educed from said bodies.

11. A musical instrument'provided with a multiplicity of sonorous bodies of ditlferent pitch, electromagnets to which said bodies are armatures, means for delivering properly timed electric pulsations to said electromagnets, and means for simultaneously shifting said electromagnets relative to said bodies to present certain thereof at greater distances than others :from their respective bodies.

12. A musical instrument provided With sonorous bodies of different pitch, electromagnets adapted to actuate the same, an intermediately jointed support, and means for moving said support toward and from said bodies.

13. A musical instrument provided with sonorous bodies of different pitch, electromagnets adapted to operate the same, and Y -sonorous bodies or different pitch, electromagnets adapted to actuate the same, a magnet-rail supporting said electromagnets divided into a plurality of sections, each of which consists of a straight bar, means for supporting said bars outot parallel with each other to present certain of the electromagnets closer to their sonorous bodies than others ot the electromagnets are to their said bodies, and means tor moving certain ends or" said bars toward and from said bodies While the other ends remain substantially stationary. l

15. A musical instrument provided With sonorous strings, clcctromagnets adapted to actuate the same, and an intermediately jointed rail supporting said electromagnets, the ends ot said rail being pivotally sup ported in the same plane with said strings,l and the rail itself being located :tar enough from said plane to support said electromagnets between itself and the strings.

1G. A musical instrument provided With strings. electromagonts, means for delivering electric pulsations thereto for the actuation of said strings, a magnet rail supporting said electromagnets and pivotally supported at its ends but jointed at an intermediate point, a pivoted brace supporting said joint, and means tor moving' said joint toward and l'rom said strings. v

17. A musical instrument provided with strings, electromagnets, means t'or delivering electric pulsations `thereto tor the actuation of said strings, an interlnediately jointed magnet-rail carrying' said eleclromafnets, arms rigidly connected with' the ends oi said rail and pivotallv supported on vertical axes in a plane coincident with said strings, and means for moving tbe jointed part of said rail toward and `from said strings.

18. A musical instrument provided with strings, electromagnets, means for delivering electric pulsations thereto for the actuation of said strings, a magnet-rail carrying `said electromagnets. and adjustable supports for the ends of said rail, said rail being'intermediately jointed.

19. A musical instrument provided with sonorous strings, electromagnets controlling the same, means for deliveringr electric pulsations to said electromaguets` a harmonic controller' for 'aryingr said pulsations, and means for varying' the distances of said electromagnets from said strings by the shifting ol' said harmonic controller.

Q0. A musical instrument provided with sonorous bodies, elcctromagnets controlliingr the same., means tor delivering,r electric pulsations to said electromagnets, means for switching to said eleetromagnets a plurality ol pulsations oit lirmjnencies other than those normal. to them, and means controlled by said switchingmeans'tor automatically varying the distances between said electromaguets and their respecti ve bodies.

21. A musical instrlunent provided with sonorous bodies, electromagnets controlling the same, means for delivering electric pulsations to said eleetromagnets, a harmonic controller for varying said pulsations, and means for automatically varying the distances of said electromagnets from said bodies by the operation ot' said harmonic controller. l

22. A musical instrument provided with sonorous, stri ugs. elect romae'nets controlling the same, uleaus 'tor delivering electric pulh sntions to said electromagnets, a magnet-rail supporting' said electromagnets, a harmonic controller adapted by its changes in position to switch an)Y of al pluralit \7 of different pulsations to saidelectromagnets. and connections between said magnet-rail and harmonic controller causing the latter to automatieally move the. former nearer said strings `when shifted to certain positions.

Q3. A musical instrument comprising nmgn'etiealljY attractive sonorous bodies and electric means including` elertrrm'iagnets for i thevbration oit said bodies, and a magnetv rail tor-the support ot' said electromagnets, said magnet rail beine; 1n a plurality of sections earb adjustable relative to said bodies.`

2l. A musical instrinnent comprising magnetically attractive sonoro'us bodies and electric means includingl electromagnets for the vibration ot' said bodies, and a magnet rail itor the support o t" said electroniagnets,

said rail being in two sections each adju'st' able relative to said bodies.

Q5. :mls-ical instrument comprising maeinelicallj attractive sonorous bodies and electric means including' electroniaenel's for the vibration ot' lsaid bodies. anda magnet rail tor the support of said elcetromagnets, said railv beiner in tivo sections' each angularly and bodily adjustable relative to said bodies.

In testimonj7 that ive clainrftbe foregoing invention. n'e havey hereunto "set our bands this 21st da \Y ot' July, 1905.j

MELVIN L. SEVER'Y'. GEORGE B. SNCLAIR.

ll-Titnesses:

Fano (ir. TILTON,

A. B. UrHAM.- 

